It is a very interesting subject to use the newly developed materials for EMI shielding on fabric. This type of materials could be integrated into the fabric during manufacturing process of fabric. I saw these types of products of nano materials on the fabric. However, the nanomaterials can be worn out through washing. Unless there is no washing after integration of nanomaterials with fabric.
To answer your question regarding the dispersion of MWCNTs, you could use DI water adding some surfactant such as SDS, SDBS.
There are many references you could follow.
One of our early work you could find in the following